The present invention relates generally to an computer system including array type storage systems, and more particularly to an computer system that selects a logical device to be moved to an other array group from among logical devices set in the storage systems and to an computer system that selects a logical device in which a path is set afresh.
There has hitherto been widely utilized a capacity-increased disk array device by loading a single storage system with plural disk drives (physical devices). Therefore, a general practice is not that a single server occupies one storage system but that plural servers share one storage system with each other in a network (e.g., Storage Area Network (SAN)) for the use of the storage systems.
There was proposed a method of improving an input/output performance of the plural logical devices set on the physical devices by equalizing loads of disk array devices having this type of plural disk drives. Specifically, an computer system has plural array groups including plural physical devices, wherein the plural logical devices are set in each of the array groups. Proposed in this type of computer system is a technology (refer to JP 11-95934 A) of equalizing the loads of the physical devices by storing a result of observing an input/output request accepting frequency with respect to every array group, every logical devices, and every physical device in a table provided in a control information memory within a control device, and replacing, with each other, the logical devices belonging to different array groups and having different input/output request accepting frequencies.